For purposes of this specification, “floor-covering” is intended to encompass both carpet and resilient flooring material. “Open seam” is intended to describe the gap formed between the vertical side edges of abutting layers of floor-covering, which gap appears when the marginal floor-covering portions adjacent the side edges are simultaneously raised by the tip passing thereunder. “Closed seam” is intended to describe the linear break between the abutting planar layers of floor-covering when they are lying flat on the sub-floor or underlay, with the side edges not yet bonded by adhesive. “Finished seam” is intended to describe the seam after applied adhesive has bonded the side edges. And “seaming adhesive” is intended to comprise liquid adhesives, thermoplastic adhesives (such as hot-melt glue) and any other form of adhesive used in the seaming of floor-covering materials as well known to those skilled in the art.
As a beginning point, it is useful to shortly describe the various forms of what is known in the industry as “resilient flooring” and to provide some background on the seaming techniques used in the past with that material. Resilient flooring is generic to: linoleum; rigid-backed vinyl (such as the material sold under the well-known trade-mark CORLON); cushion backed vinyl; and homogeneous vinyl (which is a solid layer of vinyl).
Linoleum was commonly seamed by laying the vertical side edges of adjacent layers in close abutment, folding back the adjacent marginal portions of the floor-covering layers to expose the sub-floor, applying a band of water-resistant adhesive to the sub-floor along the line of abutment using a spatula-like tool called a “spreader”, then bringing the marginal portions back down onto the sub-floor, and hand-rolling the seam to complete the operation.
The rigid-backed vinyl was seamed in the same fashion as the linoleum, except that an excess of the sub-floor adhesive was applied to the sub-floor along the line of abutment, with the hope that it would squeeze up between the abutting side edges when they were pressed down, to seal and bond them together.
In the case of the cushion-backed vinyl, the marginal portions were first laid flat on the adhesive-coated sub-floor, in the same manner as linoleum. An applicator was then used to apply low viscosity, solvent-base, liquid seaming adhesive into the closed seam. The applicator comprised a plastic squeeze bottle having a hollow, knife blade-like tip. The cushion-backed vinyl could be laterally compressed slightly, to allow penetration of the tip for application of the liquid adhesive.
In the case of the homogeneous vinyl, a narrow groove would be cut along the seam, a bead of vinyl would be laid into the groove and a hot iron would be used to melt the bead and adjacent material to thereby weld the side edges together.
From the foregoing, it will be understood that seaming involved bonding the undersurface of the floor-covering to the sub-floor with pre-applied thick adhesive and bonding the vertical side surfaces together, either by application of low viscosity, liquid adhesive or by heat welding the vinyl edges.
In the mid-eighties one of the present applicants developed a novel applicator tip for use with homogeneous vinyl. This tip was disclosed in U.S. Pat. No. 4,484,976, issued Nov. 27, 1985, which is incorporated by reference herein. Also incorporated by reference herein are the within applicant's U.S. Pat. No. 5,250,145 issued on Oct. 5, 1993; U.S. Pat. No. 6,997,227 issued on Feb. 14, 2006; and U.S. Pat. No. 7,381,289 issued on Jun. 3, 2008.
Referring to FIG. 1, a “prior art” applicator tip is shown. This prior art applicator tip was designed to wet the vertical side edges of the floor-covering with a solvent-base liquid seaming adhesive. The prior art tip was adapted to raise the flat marginal portions of the floor-covering as it passes along the seam, thereby exposing the vertical side edges while wetting them with seaming adhesive. More particularly, an installer inserts the prior art tip between the floor-covering side edges and beneath the adjacent marginal portions. He then pulls the prior art tip along the seam. The prior art tip is connected at its upper end to a plastic squeeze bottle containing a supply of seaming adhesive. The prior art tip forms a longitudinal passageway having an outlet positioned to deliver the seaming adhesive to the faces of the floor-covering side edges. The installer manually squeezes the bottle as the applicator tip is drawn along the line of abutment, to discharge the seaming adhesive.
Structurally, the prior art tip comprises an upstanding, body having, from top to bottom, a leg portion, a relatively narrow ankle portion, and a pair of opposing wedges extending from the ankle portion. The leg portion comprises coupling means at its upper end for connecting it with the seaming adhesive supply squeeze bottle, a longitudinal open-ended passageway extending downwardly through the leg, and an orifice extending through the ankle portion having communication with the longitudinal passageway to allow seaming adhesive to flow out the orifice on each side of the ankle onto the edges of the floor-covering being seamed together.
The prior art tip has worked well when used with homogeneous vinyl using solvent-based liquid seaming adhesive but, when applied to carpeting and other resilient flooring, certain problems have become evident. More particularly: the ankle portion has had to be kept quite narrow (typically 1/16″). If this is not done, the seam will open too much as the tip is moved along it. An excessive amount of seaming adhesive can then readily move down the passageway and into the open seam (this excessive flow is referred to as “flooding”). In the case of carpet, when the upraised marginal portions of the floor-covering drop back down to the sub-floor after the tip has passed, the excess seaming adhesive can get squeezed upwardly and will wick into the pile. The installer can then attempt to clean off the surface adhesive, but this is time-consuming, expensive and rarely complete. The presence of seaming adhesive on top of the seam will result in flattening of the pile fibers with traffic, thereby creating an undesired, hard, lumpy ridge running along the seam. In the case of resilient flooring, excess seaming adhesive will accumulate on top of the finished seam and is wasted and must be removed; flooding is also partly a result of having to use low viscosity, solvent-based, liquid seaming adhesive. These seaming adhesives will readily flow down the passageway and through the outlet or orifice into the open seam. It has not been possible to substitute a high viscosity, water-based liquid seaming adhesive for use with the prior tip, as it will not flow at a sufficient rate through the narrow ankle passageway and orifice (which typically has a diameter of about 0.040″). It would be desirable to use a high viscosity, water-based seaming adhesive, because it is less toxic than the solvent-based seaming adhesive. However, this has been deterred because a passageway of greater cross-section would require a thicker ankle portion, which would result in opening the seam wider, thereby inducing an unacceptable degree of flooding.
In addition, it is desirable, with resilient flooring and carpet, to apply some of the sealant to the undersurface of the marginal portions of the floor-covering, to enhance the strength and durability of the seam. Attempts to accomplish this end with the prior art tip, by delivering more sealant, simply result in more excess seaming adhesive reaching the top surface of the seam. Since the sub-floor is normally coated with a tacky adhesive, when the prior art tip is pressed down against the sub-floor and pulled along the seam the sub-floor adhesive will drag on the prior art tip and will also ball up beneath it. This commonly causes the installer using the prior art tip to lift it out of contact with the sub-floor during use. Several problems can then result. The floor-covering side edges can be spread too far apart; with the consequence that severe flooding will follow. Furthermore, the installer will have to manually press down the wetted edges as he proceeds. This means that the installer has to hold the bottle and tip with one hand, using that hand to squeeze the bottle, while he uses the other hand to press down the wetted side edges. All of this is tiring over time and requires a significant level of skill on the part of the installer. In addition, when the prior art tip is lifted, it has a tendency to skew, with the result that the application of sealant to the two side edges is somewhat uneven and erratic.
On large floor surfaces, floor-covering is installed in multiple pieces in order to fully cover the surface. During installation, the edges of the abutting layers of floor-covering are bonded or “seamed” together to form a contiguous layer of floor-covering over the floor surface. This requires that there are minimal or no gaps along the closed seam. Often, the closed seam is formed by overlapping one layer of floor-covering over another and then cutting both layers at once. This produces a closed seam that has virtually no gaps along its length. Typically, resilient flooring is seamed by laying the vertical edges of adjacent and abutting layers in close contact, folding back the adjacent marginal portions of the floor-covering to expose the sub-floor, applying a band of flooring adhesive along the line of abutment using a spreader and then bringing the marginal portions back together onto the sub-floor and rolling the seam with a hand roller to ensure adhesion between the floor-covering and the sub-floor. With certain types of resilient flooring, it is necessary that some adhesive squeeze up along the line of abutment thereby gluing the edges of abutting layers to each other in addition to the sub-floor. This technique is used in the installation of carpet as well.
This method is usually performed in stages or portions along the line of abutment. Adhesive is first applied to a span of approximately 12″ to 18″ and then the edges of the floor-covering are manually brought into close contact with one another and then hand-rolled to form the finished seam. This process is repeated along the line of abutment until the finished seam is completed. One problem with the prior art tip is that the adhesive dispenser attached to the prior art tip is oriented upwards at an angle leading in the direction that the prior tip follows to form the finished seam. As the dispenser and prior tip are advanced along the line of abutment towards a wall, the dispenser prevents the prior art tip from being advanced right up tight to the wall. To finish the seam, the prior art tip must then be turned around 180 degrees and be advanced backwards from the wall towards the point where it was stopped previously.
In the art of installing floor-covering, it is also known to use a backing tape to reinforce a finished seam. This involves applying the backing tape to the back of the floor-covering along the line of abutment. The backing tape reinforces the finished seam to provide additional resistance against the adjacent layers being pulled apart. The current method of installing a backing tape involves gluing the backing tape to the sub-floor or pad underneath the line of abutment with a floor adhesive. The marginal edge portions of the floor-covering are then glued to the backing tape.
The backing tape itself can be comprised of lines or strips of thermoplastic adhesive on its top surface running along its length. To activate the thermoplastic adhesive so that the floor-covering will bond to the backing tape, a heating iron is placed in the open seam between the floor-covering and the backing tape. The iron heats the thermoplastic adhesive until it becomes molten. The iron is then manually drawn along the backing tape to heat a portion of the backing tape adhesive. While the thermoplastic adhesive is still molten, the edges of the abutting floor-covering layers are fitted to one another and then hand-rolled such that the marginal edge portions are brought into contact with the molten adhesive and are bonded to the backing tape as the adhesive cools and sets.
There are a number of disadvantages with this method. First, no adhesive is placed between the abutting edges of the floor-covering. The only bonding that occurs is between the bottom surface of the marginal portions of the floor-covering and the backing tape. Second, there is a risk that the heat produced by the iron to melt the thermoplastic adhesive will melt or burn the floor-covering itself. Third, this method is difficult to use when making finished seams that are curved. The bulkiness of the backing tape with thermoplastic adhesive makes the tape difficult to bend and form curves. Fourth, gluing the backing tape to the sub-floor or pad makes it difficult to move the backing tape once the floor adhesive begins to set to compensate for any adjustments in placement of the floor-covering when the finished seam is formed. Lastly, this method of installation is awkward and requires considerable skill to produce a finished seam.
It is, therefore, desirable to provide an applicator tip that overcomes these problems and that can be used with floor-coverings such as carpet and resilient flooring and which is adapted to be used with high viscosity, water-based liquid seaming adhesives.